/*
 * Copyright 2022 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef SKSL_PROGRAMUSAGE
#define SKSL_PROGRAMUSAGE

#include "include/core/SkTypes.h"
#include "src/core/SkTHash.h"

namespace SkSL {
class Expression;
class FunctionDeclaration;
class ProgramElement;
class Statement;
class Variable;

/* *
 * Side-car class holding mutable information about a Program's IR
 */
class ProgramUsage {
public:
    struct VariableCounts {
        int fVarExists = 0; // if this is zero, the Variable might have already been deleted
        int fRead = 0;
        int fWrite = 0;
    };
    VariableCounts get(const Variable &) const;
    bool isDead(const Variable &) const;

    int get(const FunctionDeclaration &) const;

    void add(const Expression *expr);
    void add(const Statement *stmt);
    void add(const ProgramElement &element);
    void remove(const Expression *expr);
    void remove(const Statement *stmt);
    void remove(const ProgramElement &element);

    bool operator == (const ProgramUsage &that) const;
    bool operator != (const ProgramUsage &that) const
    {
        return !(*this == that);
    }

    skia_private::THashMap<const Variable *, VariableCounts> fVariableCounts;
    skia_private::THashMap<const FunctionDeclaration *, int> fCallCounts;
};
} // namespace SkSL

#endif
